Motorola MC14500B

The MC14500B Industrial Control Unit (ICU) is a CMOSone-bitmicroprocessor designed by Motorola for simple control applications in 1977.[1] It is well-suited to the implementation of ladder logic, and thus could be used to replace relay systems and programmable logic controllers, also intended for serial data manipulation.[2] The processor supports 16 commands, operating at a frequency of 1 MHz.[2] The MC14500B unit does not include a program counter (PC); instead, a clock signal drives a separate PC chip; therefore the size of supported memory is dependent on the implementation of that chip. It was still in production in 1995.[2]

One of the computers known to be based on this processor is the educational WDR 1-bit computer (512 bits of RAM, LED, I/O, keyboard).[3]